TiDB安装问题记录

案例1

[问题澄清]

TiDB集群安装过程中，遇到报错：

the maximum number of open file descriptors is too small, got 65536, expect greater or equal to 82920

或者

fatal: [10.8.xxx.205]: FAILED! => {"changed": false, "msg": "The default maximum number of open file descriptors is too low 4096, should be 1000000"}

[原因分析]

操作系统max open file limitation设置过小，需要增大配置.

[解决方案]

1.检查参数值：

ulimit -Sn

ulimit -Hn

修改参数值:

ulimit -HSn 1000000

2.如果测试环境使用docker配置，可以尝将docker配置文件

/usr/lib/systemd/system/docker.service的参数

LimitNOFILE=infinity

LimitNPROC=infinity

改为：

LimitNOFILE=1000000

LimitNPROC=1000000

重启docker，部署tidb

3.如果当前session设置参数不生效，改完后，新建session尝试

[参考案例]

Docker-compose 报错 the maximum number of open file descriptors is too small 是什么原因？

https://asktug.com/t/docker-compose-the-maximum-number-of-open-file-descriptors-is-too-small/183

使用 tidb-operator 部署，pd 部署成功，tikv 一直处于 CrashLoopBackOff 状态

https://asktug.com/t/tidb-operator-pd-tikv-crashloopbackoff/644

ansible集群新增节点报错

https://asktug.com/t/topic/2498

[引申学习点]

CENTOS中6和7设置参数的位置不同.可以参考以下文章

CENTOS/RHEL 7 系统中设置SYSTEMD SERVICE的ULIMIT资源限制

http://smilejay.com/2016/06/centos-7-systemd-conf-limits/

案例2

[问题澄清]

TiDB集群安装过程中报错：

Ansible FAILED! => playbook: start.yml; TASK: set_fact; message: {“msg”: “The conditional check ‘((existing_api_keys[‘json’] | selectattr(“name”, “equalto”, “grafana_apikey”)) | list) | length == 1’ failed. The error was: no test named ‘equalto’ The error appears to be in ‘/home/tidb/tidb-ansible/common_tasks/create_grafana_api_keys.yml’: line 24, column 3, but may be elsewhere in the file depending on the exact syntax problem. The offending line appears to be: - set_fact: ^ here ”}

[原因分析]

jinja的版本过低

[解决方案]

安装tidb-ansible目录中requirements.txt文件的要求更新版本

sudo pip install --upgrade -r requirements.txt

[参考案例]

请教下，执行 ansible-playbook start.yml 时报错，求解答

https://asktug.com/t/ansible-playbook-start-yml/170

[引申学习点]

了解jinja

https://jinja.palletsprojects.com/en/2.11.x/

案例3

[问题澄清]

TiDB集群安装过程中报错：

Ansible FAILED! => playbook: bootstrap.yml; TASK: check_system_static : Preflight check - Check if the operating system supports EPOLLEXCLUSIVE; message: {“changed”: true, “cmd”: “/home/tidb/deploy/epollexclusive”, “delta”: “0:00:00.007020”, “end”: “2019-10-16 10:29:15.858494”, “msg”: “non-zero return code”, “rc”: 1, “start”: “2019-10-16 10:29:15.851474”, “stderr”: “”, “stderr_lines”: [], “stdout”: “epoll_ctl with EPOLLEXCLUSIVE | EPOLLONESHOT succeeded. This is evidence of no EPOLLEXCLUSIVE support. Not using epollex polling engine.False: epollexclusive is not available”, “stdout_lines”: [“epoll_ctl with EPOLLEXCLUSIVE | EPOLLONESHOT succeeded. This is evidence of no EPOLLEXCLUSIVE support. Not using epollex polling engine.False: epollexclusive is not available”]}

[原因分析]

操作系统版本过低，为支持EPOLLEXCLUSIVE

[解决方案]

升级操作系统版本，参考安装配置建议

https://pingcap.com/docs-cn/stable/how-to/deploy/hardware-recommendations/

[参考案例]

部署TIDB EPOLLEXCLUSIVE 报错问题

https://asktug.com/t/tidb-epollexclusive/1921

[引申学习点]

一个epoll惊群导致的性能问题

https://www.ichenfu.com/2017/05/03/proxy-epoll-thundering-herd/

epoll: add EPOLLEXCLUSIVE flag